Method of producing gears



Jan. 3', 1928.

Fig.2

1,655,080 E. WILDHABER METHOD OF PRODUCING GEARS Filed Feb; 19. 1926 2 Sheets-Sheet l Fz'gfi- INVENTOR E2 932 WE'ZdZZaZIer 0 1,655,080 E. WILDHABER METHOD OF PRODUCING GEARS Fild Feb. 19. 1926 2 Sheets-Sheet 2 INVENTOR Elms? Wildhaber ATTOR Y Patent Jan. 3, 192 8.

uirian STATES 1,655,080 PATENT. OFFICE...

ERNEST wrnnmna, or, nocnns'rna, NEW YORK, Assmiroa 'ro GLEASON wonxs, or

ROCHESTER, NEW- YORK, A.

CORPORATION OF NEW YORK.

nhrnon or rnonucme GEARS.

' Application filed February in provision of a method for cutting tapered gears which will produce gears of increased strength.

Other objects of the invention will be ap: parent hereinafter from the specificatlon and is from the recitalof the appended claims.

In the accompanying drawings I have il-' lustrated several embodiments of my inventionj It will be understood, however, that the invention is capable of further modifiso cation within'its scope and within the limits of the accompanying clalms.

In the drawings: Figs-rand 2 area plan view and a side elevation respectively, showing one method of producing gears according to this invention; v v I i Fig. 3 is a side elevation, artly in section, showing a slightly mo ified way of producing curved tooth gears according to so this invention; t i 4 v Fig. 4 isv a plan view illustrating the manner of. indmg curved tooth gears according to .t is invention; 7

ig. 5 is an end elevation showing, some I as what diagrammatically, the preferred manner of applying the generatlng roll; Figs. 6 and-7 are an end elevation and a ,side. elevation respectively, illustrating diagrammaticall one of the fundamental advantages of t e present method;

,Fig. Sis a plan view of a crown ear such as mightwith this invention;

Fig. 9 is a sectional view-showing the po- 45. sition of the sphericaLface mill in cutting a constructed gear conjugate to t e crown gear of Fig. 8;"

v Fig. 10 is a side elevation, artly in sec- -tion,' illustrating a somew at modified .method of producing a bevel gear, conjugate to to a spherical profile crown gear; and

Figs. 11 and 1 are a side elevation',-partly in section and transverse sectional view,

respectivly,"of a machine such as might be employed in ra'ctisi this invention.

a It 'is well own t at an involute spur sglerical profile Q '(1 ill aii d 19,1926. Serial no. 8am.-

gear will roll with racks of difierent pres-' crown gears or, different mate'gears; I have" discovered that it is possible to use a tool whose pressure angle is different from the pressure angle of the tooth to be cut and by imparting aproper rolling motion between said tool and the gear blank to produce a tapered gear of the desired pressure angle.

The present invention permits of cutting two adjacent tooth surfaces of the blank simultaneously'without decreasing the strength of the teeth so produced as compare with the strength of the teeth of tapered gears whose tooth surfacesare out one side at a time. Heretofore, it has only been possible to out tapered gears two sides simultaneously by using male and female tools'and cutting the teeth with arallel the distance from tooth to tooth or uniform depth or by so cutitng t e blank with a male tool that the bottoms of the tooth ,spaces lie on conical surfaces whose a ex is outside the pitch cone apex of the (while the gear teeth pro needby the female tool are of constant thickness). The

duces a ear whose teet are Week at eir outer en because of the increased depth of the tooth there as compared withv its depth at its inner end. The present invention enables. tapered gearsito .be out two sides simultaneously in a manner such that the hotother method of cuttin referred to, ro-

toms of the tooth spaces, lie one cone whose apex coincides with or substantially coincides with the pitch cone apex of the blank.

In other words, the resent invention permits of the production. for tapered gears whose teeth are of gradually decreasin from their outer to their. inner on whose depth decreases in proportion to the taper'of the'gear itself in an operation which is-veryrapid.

, g Referring to the drawings byanum'erals of reference.

.cates. a rota annular face mill provided with a plum ity of cutting blades. These lades 1n the form shown are aralternate blades 11 and .12

cuttin range in pairs,

H cutting opposite side faces of the teeth of 'the blaiik. The-finish cutting ed es 13 and "14 of these blades are made wit side or pressure angles, each side having,

1 90. Here-the axis 29 of the tool is inclined than the Fressure an the gear/1 to-be cutthereby. In-

different preferabl Ia'gr'eater side or pressure ang e y le of'the tooth faces. 15

and 16 o producing a curved tooth gear with this tool the cutter'lO will berotated on its axis and simultaneously therewith: a relative motion will be imparted between the rolling to generate the tooth tool and the profiles. Ordinarily in producing a tapered ear, the tooth profiles are generated by a ro ing motion in whjch the itch surface of the blankrolls on the pitc surface, of the gear which the tool represents. With the pres v escapee.

crown gear or gear with which the blank rolls during eneration. 1

In Fig. 2 t 0 blank rolls on the pitch surface .of a nominal crown -gear,'that is, a crown gea'r whose pitchcone angle A is somewhat less than 90.' The top surface of such a crown gear is a plane Such a crown gear is emplo ed in the Gleason spiral bevel generator. I placed parallel to the axis of the nominal crown ear which the tool represents. In

. Fig. 3 t e blank rolls on the pitch surface of atrue crown gear, that is, the pitch surface of a crown gear whose-pitch cone angle 'B-is 'to' the axis 31 "of the. crown gear.

' sides actuallyconverged to a point, it would be possible to cut two tooth surfaces imultaneously and. still make the groo e bot toms intersect the pitch cone apex. But in practice'it is'necessary to'use tools of ap preciable width at their ti 5. The sides of such tools will. converge i prolonged at a omt somewhere below the tooth surface to cut. Consequently, inputting two side faces simultaneously, the groove bottoms cannot be made to-intera ectexactly the pitch 'ent invention, the .blankwill roll in the man-" cone apex.- The. nearer, however,- the theoably of p I -cone, rolling on the pitch surface o fthe 1 ustrated in Figs. 2, '3- and 5, where '18-in-' ner of a' cone of different dimension, preferg'reater dimension, than itsitch ear which the tool represents.) This is ildicatesfthe axis of the blank, 19' its apex,20 itspitch surface, .21. its pitch coneangle, 22

retical point of convergence of the tool sides the-rolling surface of the blank during gen- Figsflfi and 7." In these fi urea, 32 indicates .eration, and 23 the cone an le of this surface. The cone surface 2, w, ich in the emsurface 24 of neous axis or and bla' bodiment shown lies outside of the pitch surfac'e20 ,of ,the blank, rolls on the pitch the gear which the tool represents.) In Fig. 5,. 25 indicates the instantapomt of rolling movement of tool and blank at any instantand 26 and 27 indicate npoints of contact between the tool The modified rolling motion employed in gractising this invention'm'apermits of proucing gears of the desi pressureangle with a toolwhose pressure angle is greater than thisdesired angle. At the same'time,

any desired character.

I as will be explained more fully faces are out one si e at a time.-

hereinafter, simultaneously two-tooth's' es may be cut without decreasin the strength of the gear] as compared .wit ears whose-tooth s The rolling.

a tool whose pressure ang e is the same 'as' the pressurejangle of the tooth to be produced while. 33, indicates. a 'tooi, suchas might begem loyed in this invention, whose pressure; .ang e 18 greater than the ress'ure angle, of the teeth to be cut. It will noted that the sides of the tool 32 converge at a point 34 which isa substantial distance :beow the'bot-t'om' of the groove on slot intermediate the gear teeth 36, while the sides of the tool 33 conver at a. point 37 which If-gears could be cut with atool whose' ere the axis 29 of .the tool is -1liesbut a slight istance below "the tooth .groo've bottom. In" cutting ears taneousl angle, as tool 32, the -parts of; a cone s oove bottoms will be 2 outside of th pitch cone blank. By. decreasin the intersection point of e .toothbottom, as by 'emp oying a tool 33 of pressure le,-the-gfoove bottoms -may be-made parts 0 a cone surface'40, in .thepresentinvention, whose apex coincid'es with or substantially coincides with .the. pitch cone apex 39 of theblank. The iadvantage-of-this nstruotion' is that the teetyh'of tapering depth two sides simul '.'with a tool ,of usual pressure acesuch as 38 whose cone apex ,lies a considerable distance i5pex'39 of the stance-of the. 1 sides fromthe teeth taper in depth in proportion to the taper of the gear itself and consequently the profile of the teeth is the same throughout their length, the teeth are of substantiall uniform strength throughout their lengt curvature of the teeth of'curved tooth gears produced with this invention, the bottoms of the grooves may be made to actually pass through the cone apex.

Fig 4 illustrates one application of the present invention to the grinding of gears. The rotary annular grinding wheel 41, the pressure angle of Whose sides is larger than the-pressure angle of the tooth sides to be v ground, is rotated in engagement with the. gear 42 in the same way in which the tool .10 moves. That, is, the wheel rotates on its axis 43 while a relative rolling movement is imparted between the tool and the gear inwhich the blank rolls with a cone of dif- .ferent dimension than its pitch cone on the pitch surface of the gear which the tool represents. This invention has a special advantage in grinding, since the grinding stock of a grinding wheel maybe made larger than that of grinding wheels whose pressure basic gears whose teeth are of straight profile. The present invention may be applied also to the production of gears whose tooth surfaces are conjugate to spherical surfaces Fig. 8 illustrates a crown gear 45 provided with longitudinally curved spherical tooth surfaces. The convex pitch lines 46 are-arcs of circles whose centers are at 47,47, 474, etc., while the concave pitch lines 48 are arcs of circleswhose centers are at 49, 49',

.49, ete." T-he centers 47 47, 47", and 49,

49', 497, all lie on the same circle 50. The

tooth surfaces of this crown gear are parts of convex and concave .spherieal toothsure. faces The convex tooth surfaces of the crown gear are parts of convex spherical surfaces whose centers 51, 51, 51",". etc., lie on a circle 54, which appears as a straight line in Fig.4 9, which is situated below the pitch plane 52 of the crown gear. The concave. tooth surfaces are parts of concave etc.,1i.e on a circle which is situated above \s pherioal surfaces whose centers 53, 53, 53",

W the pitch plane of the crown gear. For prol dyeing theoretically correct gearing the distance of the circle 55, above the pitch plane 52 should be the same as the distanceof the circle 54 below that-plane. To produce a gear conjugate to the crown ear 45, the axis 56 of the tool must be so incllned as to pass through the center 51 of a convex spherical tooth surface and also through the center 53 of a concave spherical In other words, the axis 56 toot-l1 surface. must be the connecting line between the two centers, as shown in Fig. 9. A rotary face mill 60 is shown in this position in this figure. It consists of a body portion 61 and a number of inserted blades 62 whose outside and inside cutting'edges, 63 and 64 respec tively, are parts of convex and concave spherical surfaces, respectively, having the same radius as the tooth surfaces to be represented and whose centers coincide with the centers 51 and 53 respectively, during the cut. The cutting operation as already de scribed consists of a rotary motion of the tool and a simultaneous relative rollin movement between the tool and blank, in which the rolling surface of the blank is a cone of different and preferably greatercone angle than the pitch cone angle of the blank.

Fig. 10 illustrates a slightly modified way of generation in which the crown gear is of a modified form. Here the cutter 60 represents and constitutes a tooth of a nominal crown gear, the pitch surface of which is not exactly a plane, but a conical surface, having its pitch cone angle 66 slightly less than This form of crown gear, as already explained, is employed in the Gleason spiral bevel gear generator. Here the axis 67 of the tool is parallel tothe axis 68 of the crown gear, but again passes through the sphere centers 69 and 70 of the tooth profiles.

In producing gears whose tooth surfaces areconjugate to spherical surfaces of revolution, with this invention, the same relative rolling movement already described is imparted between tool and blank. In this relative rolling movement thehlanlr 70' whose axis is at 7 5 rolls as though with a surface 71 preferably outside its pitch surface 72 on the pitch surface of the gear represented by the tool: As illustrated in Fig. 10, the cone angle '73 of the rolling surface is greater than the pitch cone angle 74.

One form of machine such as might be employed in producing a 'gear according to this invention is illustrated in Figs. 11 and 12. The tool employed is shown as a grindiing wheel 80 of circular arc profile. This tool is mounted on a spindle 8ljwhich is journaled in suitable bearings 82 in the frame of the machine and which is driven from any suitable source of power as a mo tor 83 through the spur gearing 84. The

blank .85 is mounted on the spindle 86. To

produce the required rollingmotion between thetool .and blank during cutting, a master ear 87 is secured to the blank spindle 86.

his master gear will have a' pitch cone larger than the pitch cone of the blank'or will be so positioned as to roll on a conical surface other than its pitch cone surface. This master gear meshes with a gear segment 88 which is secured to the frame of the machine. The pitch cone angle of the gear.

segment 88 is that of the gear. which the tool represents. If a trfiecrown gear it is 90. If a nominal crown gear, it will be something slightly less than 90. Ifthe gear being produced is the generated'member of a gear pair in which one member isv non-generated, the pitch coneangle of-the segment 88 may be the same or approximately the same as the pitch cone angle of the gear with which the gear being pro-- ducedis to mesh. The rolling motion. is

imparted to the blankspindle as follows segment 91 is oscillated to causethe blank 80 spindle'to roll across the face of the tool.

The oscillatory movement of the segment 91, ,is derived from a pulley 92, or any other suitable source of ower. This pulley 92 is mounted on a sha t 93 to which is keyed a helical ear-94; meshing with a helical gear 95 whic is keyed to a vertical shaft 96. which is journaled in the frame and to which is secured. at its upper end a crank. --member 97 which is connected, through the block 98and slot-99 with the segment 91. Through the means described. an oscillatory movement is imparted to the carrier 89 cansing the master gear 87 to roll on the gear segment 88. The gear blank .rollsinone 4b.

' during the indexing period. The withdrawdirection for generation an'd'is Withdrawn ing mechanism shown comprises a cam 100 which is" secured to' the shaft 93 and which actuates t he bell crank level :101 which is ,piv'oted'at 102 to' the frame; The bell crank lever is connected through the link 103 with a 'meinberI-104. which is provided'witha' .'flange,"105' seating in asuitable recess in a cylindrical support 106 which is slidably,

mounted in the frame. The carrier 89 is mounted rotatably on this support 106.

1 Normally, that is, duringthe cutting operashown,

tion the carrier is \held in the position withvthe master gear 87 in engagethe powerful coil 'spring'107 which is interposed between the support 106 and the base -of the frame. When the bell crank lever is rocked about its pivot 102 the support 106 and the carrier. 89 are foreeddown against the resistance of the spring 107 to withdraw the master gear from enga ement w th the segment 88. A stud 108 on t e flanged mem her 104 passes through the carrier 89. A4

coil spring 109 mounted on this stud and interposed between the washers 110 serves to retain the carrier at all times in osition on the support 106. The withdrawa of the blank from cutting position and the reversal of movement of the carrier permit of index- 76 ing, a brake 1 11. preventing rotation of the blank spindle during reversal, The blank turns only during the cutting strokeiand is indexed one or moreteeth, preferably several teeth, durin the time it is out of engagement with t ie'tool.

Instead; of produclng both members of a pair of generated gears with a tool of ,increased pressure angle; one member may be produced in the usual wa and the other member, preferably the pinion, produced'according to the method of th1s invention.- In this case, should it be desired to produce gears conjugate to acrown gear whose tooth surfaces are spherical, itwill be necessary, to producetheoretically accurate teeth, tososet the axis of the tool used to produce the gear being generated by the new method that the sphere centers 51 and .53 of the tooth surfaces of this gear willbe at the same distance from 9.1 the apex of the crown gear as the centers112 and 113 of the tool employed to produce in the usual method the other gear. This is indicated diagrammatically in Fig. 9, where the axis 114 of the tool employedtoproduce the mate gear by the usual method is inclined to the drawing plane at such an angle that the sphere centers 112 and 113. of the cutting edges of the tool are at the same distance from, the a ex as the centers 51 and 53 are,

Theoretica y correct matinggearspgay also be cut with this invention by using tools of diflferent increased pressure angles.

In.generating gurved tooth bevel gears in the i sual rolling motion, about .two intersect: 1 m

ing' axes,- with spl'herical tools of different pressure angles, t e sphere radii ofthe cutting edges of thetools should be the same. In this case,'-the cutter'diameterswillibe un-- equal. 1

the

- v 15 he present inventioniscapplica production of 'ears-where'both members are generated or w ere onlylone member is en- 7 eratedandthathya 'ghng movemento the blank substantially on --'the pitch surface of the non-generated membe1; It is app icable to the production of both bevel and ypoid ears. f t

While I have illustrated certain preferred embodiments of my invention, it wlll. be un derstood that this invention is capableof further modification within the'limits of the I disclosure and (the scope of the appended claims and that this application is intended \to cover any variations, uses, or adaptations 9f my inventin, followinga' inf genc fiily lle principles of the in ventionfand' including suchdepartures from :the present disclosure as come withinknown or Customary practice in the gear art and as may be'applied -to the essential features hereinbefore set forth and as fall within the limits of the accompan ing claims.

aving thus described my invention what I claim is 1. The method of producing gears which consists in cutting two adjacent side faces of a gear blank simultaneously by moving a pair of cutting ed 'es adapted to cut opposite side faces of t e gear teeth and having pressure angles greater than the pressure angles of the tooth sides to be cut thereby,

across the face of a tapered gear blank while imparting arelative rolling movement between said tool andblank in the manner of a conical body of difierent dimension than the pitch cone of the blank rolling on the pitch surface of the gear represented by said cutting edges.

2. The method of producing gears which consists in cutting two adjacent side faces of a gear blank simultaneously by moving a tool, Whose side cutting edges have pressure angles greater than the pressure angles of the tooth sides to be cut thereby, across the 'face of a tapered gear blank while imparting a relative rolling movement between said tool and the blank in the manner of a cone of greater dimension than the pitch cone of the blank rolling on the pitch surface of the gear which-the tool represents. a

3. Themethod of producing gears which consists in moving-a pair of cutting edges vadapted to cut opposite side tooth faces of the gearteeth and having pressureangles greaterthan the pressure angles of the tooth sides to be cut thereby, in concentric curved paths across the face of a tapered gear blank to produce two tooth faces onthe blank s1- multaneously, and simultaneously imparting a relative rolling motion between the cutting edges and blank as though the blank were rollingwith a cone of greater dimension than its pitch cone on the pitch surface of a basic gear represented by said cutting edges.

a. The method of producing gears which consists inselecting a tool, provided with separate side cutting edges whose pressure angles are greater than the pressure angles of the tooth sides to be cut thereby, moving said tool 'in a curved path across the face 7 of the blank to produce two tooth faces on the blank simultaneously, and simultaneously imparting a relative rolling motion between tool and blank in the manner of a cone of difierent dimension than the pitch cone of the blank rolling on the pitch surface of the gear which the tool represents,

5. The method of producing gears which v consists 'in selecting a t ol, provided with separate side cutting edges whose pressure angles are greater than the pressure angles provided with a plurality of finish cutting edges, certain of which are adapted to cut one side face of the blank and others a different side face and each of which is of greater pressure angle than the pressure angleof the tooth side to be cut thereby, and rotating said tool in engagement with the blank'while imparting a relative rolling movement'between said tool and blank in the manner of a cone of different dimension than the'pitch cone of the blank rolling on the pitch surface of the gear which the tool represents.

7. The method of producing gearswhich consists in selecting a rotary annular tool, provided with a plurality of finish cutting edges, certain of which are adapted to cut one side face of the blank and others a.

different side face and each of which is of greater pressure angle than the pressure angle of the tooth side to be cut thereby, and rotating said tool in engagement with the blank while imparting a relative rolling movement between said tool and" blank in 'mannerof a cone of greater dimension than the pitch cone of the blank rolling on the pitch surface of the gear which the tool represents.

8. The method of producing gears which consists in selecting a rotary annular tool, provided with a plurality of finish cutting edges of circular profile, certain of which are adapted to cut'one side face of the blank err and others a different side face and each of which is of greater pressure angle than the pressure angle of the tooth side to be out thereby, and rptating said tool in'engagement with the blank while imparting a relative rolling motion between said tool and blank in the manner of a cone of different dimension than the pitch/cone of the blank rolling on the pitch surface of the "gearfwhich the tool represents.

9. The method of producing gears which consists in selecting arotary annular tool, provided with a plurality of finish cutting edges of circular profile, certain of which are adapted to cut one side face of the blank thereby, 'and rotating said tool in engageand others a different side face and each of r which is of greater pressure angle than the pressure angle of the tooth side to be cut I the pitch surface of the gear which the tool represents.

10. The method of producing tapered gears which consists in moving a tool, hav1ng' a side cutting edge whose pressureangle is greater than the pressure angle of'the tooth side to be cut thereby, across th'e'face of a tapered' ear blank while imparting a'relative rolling movement between tool and blank in the. manner of a cone 'of greater dimension than the pitch cone of the blank rolling on the pitch surface of the gear which the tool represents; 11. The method of producing tapered gears which consists in moving a tool, having a side cutting edge whose pressure angle isgreater than the pressure angle of the tooth side to be cut thereby, in a curved path across the, face of a tapered gear blank while -imparting a relative rolling movement be-' tweenvsaid tool and blank in the manner of a cone of greater dimension than the pitch cone of the blank rolling on the pitch surface of the gear which the tool represents.

12. The, method of producing tapered gears which consists in rotating atool, provided with an annular cutting portion whose pressure angle is greater than the 'pressure angle ofthe tooth surface to be cut, in ennally curved tooth gears which consists in rotating a tool, provided with an annular cutting portion of circular profile whose pressurelangle is greater than the pressure angle of the tooth surface to be cut,4.in engagement with-a gear blank while impartin I a relative rolling movement between saidvtoo and blank in the manner of a cone of greater dimension than-the pitch cone of the blank rollingon'the pitch surface. of a gear which the tool represents, I ERNEST WILDHABER. 

